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Intangible Assets - Major Classes of Amortizable Intangible Assets (Detail) - USD ($) $ in Millions | Mar. 31, 2019 | Dec. 31, 2018
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Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, net | $ 1,841.4 | $ 1,773.0
Expiration Lists [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 3,529.6 | 3,379.4
Accumulated amortization | (1,758.8) | (1,676.8)
Amortizable intangible assets, net | 1,770.8 | 1,702.6
Non-Compete Agreements [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 60.7 | 58.0
Accumulated amortization | (49.8) | (48.5)
Amortizable intangible assets, net | 10.9 | 9.5
Trade Names [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Amortizable intangible assets, gross | 86.4 | 86.0
Accumulated amortization | (26.7) | (25.1)
Amortizable intangible assets, net | $ 59.7 | $ 60.9

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- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 928 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph ((a)(1),(b)) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274 + Details
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